A prior-art snowmobile typically includes a hood and a belly pan such as the ones illustrated in FIGS. 1 and 2, respectively. The hood and belly pan cooperate to enclose the engine, defining a forward portion of an engine compartment of a snowmobile. As shown in FIG. 1, a hood 11 includes at least one air inlet 11a for admitting ambient air into the engine compartment of the snowmobile, for cooling the engine and/or for supplying air to the engine. The air inlets are disposed with filtering grilles to inhibit snow or other debris from entering the engine compartment.
As shown in FIG. 2, a conventional belly pan 20 includes an underbelly 21, left and right side walls 22, 23 rising upwardly from the sides of the underbelly 21, and a front wall 24 extending upwardly from the front of the underbelly to define an open structure adapted to partially enclose a forward portion of the engine. The front wall 24 also includes a bumper 25, usually molded integrally with the belly pan 20. As noted above, the hood of FIG. 1 closes over the belly pan of FIG. 2 to enclose a forward portion of the engine compartment.
As is known in the art, the belly pan extends rearwardly under the engine, tuned pipe and other engine accessories to a point where the tunnel attaches to the engine cradle. The conventional, prior-art belly pan therefore has a rear opening for accepting the front of the tunnel, gas tank and other forwardly mounted components of the vehicle. Sometimes, the bottom of the belly pan is cut away so as to have the shape of the bottom of the engine cradle, which is normally made of sheet metal. Because the belly pan is normally made of plastic and the shape is not enclosed, the overall construction is very flexible and thus the attachment to the snowmobile has to be reinforced with metal brackets to ensure that the belly pan does not deform or break under its own weight.
In the prior art, however, the air inlets do not direct the air to the most effective locations within the engine compartment. Thus, there is a natural tendency to provide more air inlets than would be needed if the air were guided to the right places to ensure sufficient air cooling of the engine. By providing an excessive number (or excessive size) of air inlets, at least two shortcomings arise. First, the engine compartment becomes vulnerable to penetration of snow, particularly powdery snow, which can then clog up the engine compartment and the air inlets. Second, the snowmobile is noisier when many air inlets are provided. In other words, noise suppression is diminished when the size and/or number of air inlets is increased.
Therefore, it would be highly desirable to provide a nose cone for a snowmobile that overcomes at least one of the deficiencies of the prior art as described above.